A solar battery is one of the most important energy sources available for scientists to save energy consumption, and serves as a spare source while normal power supply shuts down. There are well-known methods for manufacturing several types of solar battery to improve efficiency of energy transformation and save cost. The solar battery in the prior arts has low efficiency of energy transformation because most power of incident light is absorbed by the silicon substrate, which is thick, about hundreds of micrometers, and only little portion of light can be converted into electric energy by active regions in the substrate.